Concrete has been used since antiquity for construction. The Coliseum of Rome was made of concrete. Concrete is well suited to many construction applications. Concrete has, however, a drawback in that it has only very limited tensile strength. For many decades, metal reinforcing rods have been used to remedy this limitation of concrete. The rods are set into place in a mold and concrete is poured into the mold and over and around the rods.
Placing the rods is a labor-intensive task which has prompted investigators to explore other ways of remedying the tensile-strength limitation of concrete. Experience also shows that it can occasionally happen that the rods shift during pouring, which can lead to the rods being in the wrong place when the concrete cures.
It has become commonplace in recent years to augment the tensile strength of concrete with synthetic fibers. In some applications the fiber can serve as a replacement for the reinforcing rods. In other applications it is desirable to use both fiber and reinforcing rods.
In some applications it is desirable to add coloring agents to concrete.
Makers of concrete fiber additives and concrete colorants often make their products available in bags that are able to dissolve when mixed with concrete. Thus in a typical application, a user who wishes to add some predetermined amount of fiber or colorant to a concrete batch will simply throw the bags into the mixer. The bags get wet and dissolve and the mixing process will distribute the fiber or colorant evenly through the batch. The bag is made from a material selected so that it dissolves and so that it does not harm the concrete when it is dissolved.
One way that a user may add bags to a load is to count a desired number of bags, hold the bags in one arm, climb the rear-mounted ladder on the concrete mixer (using only the other arm), and drop the bags into the loading funnel. This can be awkward and, like any maneuver in which someone is off the ground, presents a risk that the person may fall.
Several complicated devices have been proposed to deal with loading fiber into concrete mixes, including U.S. Pat. Nos. 5,118,225 to Koch et al., 5,947,645 to Rixon et al., and 6,283,327 to Rubtsov. These devices are complicated and expensive and have many moving parts.
There is thus a need for a simple and inexpensive apparatus for loading bags of fiber and colorants into concrete mixers.
A loading apparatus includes a loading tube with an input end and an output end, the input end positioned between three and six feet above a surface, the output end positioned between six and twenty feet above the surface. The surface is sufficiently strong to support a concrete mixer. The loading tube further comprises at least one nozzle positioned at the loading tube between the input end and the output end, the nozzle disposed so that air passing through the nozzle into the loading tube flows toward the output end. A valve is connected with the at least one nozzle, disposed to permit and deny air flow through the valve to the at least one nozzle. To use the apparatus, the loading tube and a concrete mixer are positioned so that the fill opening of the mixer is below the output end. Air is caused to flow through the at least one nozzle. A predetermined number of water-soluble bags of material are counted, and the bags are placed, one by one, into the input end of the tube. They are first sucked, and then pushed, into the mixer, where bags dissolve, releasing their contents into the mixer.